Study On The Torsional Performance Of The Horizontally Curved Compsoite Box Girders With Corrugated Steel Web

In the actual operation, thin walled curved box girder bridge often bears large torque. Cross section of the box girder generates rigid torsional deformation, accompanied by distortion deformation. Compared with the concrete box girder, torsional stiffness and distortion stiffness of composite box girder with corrugated steel web go down, leading the section to produce torsion deformation and distortion deformation more easily. Meanwhile as longitudinal elastic modulus of the corrugated steel web is small, stress on top and bottom concrete board increases a lot in the same vertical load. In consequence, torsion and distortion study and analysis of this type curved boxgirder is of great importance.In this paper, study and analysis had been carried on the torsion, distortion and diaphragm plate set ofthe composite curved box girder. The specific research results as follows:(1)Taking the longitudinal warping displacement theory into account and combined with the characteristics of corrugated steel web, torsion moment and torsional stress calculation formulas were proposed. Comparing the theoretical value of the real bridge with the finite element value indicated that torsion analysis theory had high accuracy.(2) Based on the cross-section distortion warping function calculated by the elastic analysis and combined with the corrugated steel web's transverse bending properties and considering the influence of the curvature of cross section distortion angle, the method of calculating distortion stress was derived. Comparing the theoretical calculating value and finite element calculating value indicated that curved box girder distortion theory had high accuracy.(3) Comparing the torsion and distortion performance differences among three kinds of web, including corrugated steel web plate, flat steel web and ordinary concrete box girder web. The results showed that the corrugated steel web plate box girder and flat steel box girder web nearly had the same torsional stiffness, but the former' resistance to distortion was far superior than the latter. The ordinary concrete box girder' resistance to torsion and distortion was superior than the formers.(4) Ansysing the effects of curvature to the torsion and distortion of curved box girder with corrugated steel web. The results showed that with the increase of the curvature, torsional double twisting moment and normal stress increases linearly.Curvature effect on the distortion effect under partial loads was little, however the effect on its own weight was obvious.(5) Ansysing the effects of diaphragm plate to the distortion stress and distortion with finite element (Ansys), and studying the relationship between density of diaphragm plate and distortion. The diaphragm spacing formulas was proposed considering H/B and R of the curved box girder, which could provide reference for the actual bridge.